On-line Non-destructive Measurement of Solidification Shell Thickness of Continuous Casting Steel Slabs

Abstract

It is very important to measure solidification shell thickness of C.C. slabs for a good and fast control system of a production line. There have been so far only destructive methods and theoretical calculation for the shell thickness estimation.
We have developed the method of nondestructive, real time and quasi-contionuous measurement of the shell thickness utilizing the technique of electromagnetic generation and detection of ultrasonic waves and successfully tested it in our C.C. production line.
The measurement system was installed about six meters below the molten steel level and measurements were done every one to two minutes for long time, during that time casting speed was changed. The measured results showed that this method could be applied to measure the shell thickness not only for stable casting conditions but also for dynamically changing casting conditions.